In laundering, it is common to treat various types of fabrics with chemical compounds which have long been known to possess the qualities of imparting softness, antistatic properties, bacteriostatic properties, moth-proofing and other conditioning treatment to render them soft to the touch, bacteria resistant, deodorized, etc. In both commercial and home launderies, it is currently the practice to treat such fabrics with an adjuvant in the washer, usually during the final deep rinse cycle after it has been washed.
As a result of prior laundering, residual soaps and detergents are present on the fabric. Some fabric conditioning agents are cationic, are incompatible with the anionic occuluded soaps and detergents and suffer loss of effectiveness by mutual precipitation in contact with the residual soap or detergent even when the conditioning agents are added in the final rinse. Although some of said conditioners are expressly marketed for use during the wash cycle, such compounds are usually merely more concentrated forms of the rinse cycle additives and share the common disadvantage of loss of effectiveness due to reaction with residual soaps and detergents. Additionally, most of such conditioners now commercially available were devised at a time when cotton was the more common fabric being treated. More recently however, the fabric mix of the average wash load has changed with more than one-half being composed of synthetic fibres which present different problems and necessitate different considerations for conditioning. For example, synthetic fibres tend to take up less of cationic softeners which are ionized in the wash or rinse water than do cotton fibres because they have fewer negative charges to attract the positive, cationic softening ingredient. Another consideration related to the successful use of such conditioning products is convenience of use. A major disadvantage of washer additives has been the fact that the user often must stay in the laundry area or return to the laundry area to add the adjuvant at the proper time and often fails to do so thereby resulting in repeated rinse cycles until the adjuvant is timely added or more often, failure to add conditioner completely. Additionally, such compositions are not generally pre-measured with the result that the user often either uses an amount insufficient to adequately condition the fabric or wastes the product by using excessive amounts.
More recently, various and ever increasing proposals for effecting such fabric conditioning in the dryer have been proposed as a viable alternative to those above enumerated. Such proposals have taken the form of sprays, flexible substrates bearing the conditioning agents, solid plastic balls containing such agents or substrates containing adjuvant affixed to the wall of the dryer. None of these proposals have been without serious disadvantages however. For example, the use of sprays of fabric softeners or other applications of such liquids to the laundry in the dryer usually involves the same problems of applications of insufficient or excessive amounts of material. Additionally, with such sprayed additives, it is difficult to treat multiple loads of fabrics consecutively, e.g., after the first load is completed, since the hot dryer tends to vaporize the additive initially venting out major proportions of the adjuvant. Moreover, it has been found that humidity sensors or other devices functioning as automatic shut-off mechanisms as well as the heating elements of the dryer, tend to become coated with such sprays after repeated use rendering such components of the dryer inoperable. Corrosion of the dryer drum is often another detrimental effect encountered with prolonged use of such aerosol spray products. Staining, spotting or other detrimental effects due to local applications of excess conditioning agent are often observed. If a flexible sheet such as paper or cloth is impregnated with conditioning agents and the product is tumbled with laundry, staining is often observed due to temporary entrapment of the flexible article in the laundry being treated which causes the application of more conditioning agent than is desirable at particular locations on the treated fabrics. Such local over applications may also be caused by cracking or flaking off of the conditioning agent when the flexible substrate is folded, creased, twisted, bent, etc. during tumbling with the laundry. Additionally, such sheets may obstruct the dryer vent causing high heat buildup in the dryer. And finally, even if none of these detriments occur, such sheets must be removed from the clothes being treated adding another step to the laundry process.
In the past, it has been suggested that an improved method of applying conditioning agent to fibrous materials in the dryer would involve the use of form-retaining bases for such material so that the base would not bend, fold, crease or flex sufficiently to cause the conditioning agent to flake off. Thus solids such as polystyrene balls have been taught to be useful when coated with fabric conditioner. Such articles tumble with the laundry and although they are not difficult to locate after use, must be found and separated from the laundry after completion of the treatment cycle again adding an additional step to an already tedious operation.
It is an object of this invention to provide a fabric conditioning composition which contains premeasured amounts of conditioning agents and thereby eliminates problems derived from insufficient or excessive application of the same.
It is another object of this invention to provide a fabric conditioner which is suitable for use in the dryer while conveying softness after use that is at least comparable to that obtained in the washer.
Still another object is to provide a fabric conditioner which may be used without spotting and staining of the fabrics being treated under the normal conditions met in the automatic dryer.
A further object of the invention is to provide a fabric conditioner composition suitable for use in the dryer which need not be located and separated from the items treated at the completion of the treatment.
Another object is to provide a method for conditioning fabrics as well as a method for controlling the release of conditioning agents to the fabrics while in the dryer.
Another object is to provide a fabric conditioner composition which imparts softness to the surface of the fabrics while preserving absorbancy of the internal weave.